Answer:
i say it doest hurt that much because there basicly cutting loose skin... there cutting between two muscles and they not cutting anything important its just loose skin between two muscles so its like cutting loose skin of a wound or something. so yeah there not going to cut any veins or important muscles so it doest hurt.
It definitely isn't just loose skin. You have muscles and tissue there but it just isn't as "active" or thick as the edges. Just use your finger to feel the center. Theres definitely something more than loose tissue. They're pretty painful. I don't personally have one but have known people who do. Tongue splits do usually heal pretty fast though. You'd be able to move the pieces separately a few days later. The best way to get an idea is watch videos of the procedure. There are a ton on youtube of the actual splitting and even some of people who are talking about the experience.